Structurally Sound Concrete Masonry Units

Concrete masonry units (CMUs) are typically used for foundation and some exterior walls. They are commonly referred to as simply concrete blocks or cinder blocks. CMUs themselves are made primarily from Portland cement, gravel, sand, and water. They are more energy-efficient, fire-resistant, and low-maintenance compared to framed walls.

CMUs
typically have 8x8x16-inch dimensions. While building walls are the
most common application for concrete masonry units, other uses include retaining walls,
chimneys, fireplaces, and other fire-safe enclosures. CMU walls are
constructed by stacking units, in a staggered pattern, with mortar in
between—much like any masonry structure or facade such as brick,
natural stone, etc. What makes CMUs so much more structurally sound is
that they are designed with large holes through the top and bottom
(unexposed) sides of the block, giving them a sort of
rectangular-letter-B shape from above, so that reinforcing steel bars may be inserted vertically into the wall and then filled with concrete to solidify the entire system.

Concrete
masonry units can also be manufactured to provide a certain
architectural flare as well. Split-face blocks are cut by machines to
deliberately expose a rough, stone-like texture—giving them a sort
of fractured rock aesthetic. CMUs may also be slotted or glazed
depending on the application and desired function or aesthetic.